Dietary Sources of Fructose and Its Association with Fatty Liver in Mexican Young Adults

Nutrients 2019, 11, 522; doi:10.3390/nu11030522 —

Cantoral A, Contreras-Manzano A, Luna-Villa L,
et al.

Download Research Study PDF

Objective

• To
  assess the consumption of dietary fructose according to: 1) classification
  of hepatic steatosis by two indexes and 2) diagnosis of NAFLD by MRI.

Background

• Previous studies have shown that consumption of
  fructose through soft drinks and other beverages is higher in NAFLD
  patients than in controls.
• Mexico has one of the highest per capita intake
  of soft drinks worldwide and their consumption is particularly high in the
  19 to 29 year-old age group.
• The present study sought to compare the intakes
  of different dietary sources of fructose in relation to two liver indexes
  that predict hepatic steatosis and the identification of NAFLD by MRI in
  young adults in Mexico.

Methods

• A cross-sectional analysis was performed in a
  sample of 100 healthy young adults living in Mexico City between October
  of 2016 and May of 2017. Participants were selected from the Early Life
  Exposure in Mexico to Environmental Toxicants (ELEMENT) cohort study.
• For the present study, participants were
  evaluated during a weekend day at the research center after 10 hours of
  fasting. A blood sample and anthropometric measures were obtained. In
  order to estimate the hepatic triglyceride content, proton magnetic
  resonance spectroscopy (PMRS) was performed. Also, a trained nutritionist
  administered a validated semi-quantitative food frequency questionnaire
  (FFQ) and a lifestyle questionnaire.
• Measurement of liver fat content and diagnosis
  of NAFLD was made by MRI, and a fasting blood sample was obtained to
  quantify glucose, triglycerides and hepatic enzymes (ALT, AST, GGT) using
  a bench clinical chemistry analyzer. 
  The Hepatic Steatosis Index (HSI) was estimated using the ALT/AST
  ratio, BMI, sex, and impaired fasting glucose (IFG) blood levels (>110
  mg/dL).

Findings

• The study sample had a mean age of 21 years,
  54% were male, 52% were classified as low SES and 56% of participants were
  not physically active.
• According to the MRI, 18% of the participants
  had the diagnosis of NAFLD (>5% of triglyceride content in the hepatocytes),
  and according to HSI and FLI, 44% and 46% of the participants presented hepatic
  steatosis, respectively.
• The comparison between the true positive
  participants and the healthy participants showed that the true positive
  participants had an elevated risk in almost all the parameters in a higher
  level.  When comparing those
  classified as false positive versus those in the healthy category, BMI was
  2.3 to 3 times higher in the false positive group according to the HSI and
  FLI, respectively.
• For the false positive participants in the FLI
  the risk is significantly higher in the variable ALT (RRR = 1.10, 95%CI
  1.02–1.20) compared to healthy participants.
• For the total sample, dietary information
  showed that the median energy intake was 2689 Kcal with approximately 56%
  of the calories from carbohydrates, 33% from lipids, and 13% from proteins.
  The median intake of SSB was 720 mL, with the main contributor to SSB
  being soda (specifically cola-type) which contributed 45% of the total
  SSB, followed by sugar-sweetened commercial fruit beverages and home-made
  fruit beverages with 22%.
• Those with negative FLI (score < 30)
  consumed statistically less energy (kcal) and total grams of carbohydrates
  per day, but also reported consuming more calories from proteins and
  lipids as a percentage of the total calories, compared to those classified
  as positive FLI (score ≥ 30) and also compared to those classified as
  false positives.
• The dietary intake of almost all dietary
  sources of fructose were higher in those classified with steatosis by both
  indexes. 
• When the consumption of the different beverages
  included in the SSB category was compared, the soda intake was
  statistically higher in FLI false positive than in negative subjects.  In the case of those classified as NAFLD,
  the median intake of natural fruit juices was statistically higher
  compared to those classified as non-NAFLD (146 versus 0 mL/day).

Conclusions

• Sugar-sweetened beverages (SSB) and juices were
  consumed significantly more by those with steatosis by FLI and NAFLD
  suggesting that SSB intake is linked to metabolic alterations that predict
  the risk of having NAFLD at a young age.
• This study adds to the existing evidence
  linking SBB intake with NAFLD, a disease that is increasing in
  Mexico.  Therefore, more public
  health action is needed to reduce the intake of fructose, as sucrose or
  HFCS, especially from SSB that are highly consumed in Mexico and in other populations.
• As obesity is currently one of the biggest
  health problems in Mexico, and it is related to the incidence of NAFLD,
  more studies are needed to measure the prevalence of NAFLD in relation to
  dietary components.

Points to Consider

• The limited sample size and the cross-sectional nature of this
  analysis limits the ability to draw conclusions regarding the effect of increased
  fructose consumption, mainly through SSB, on the natural history or progression
  of NAFLD in this population.
• It is possible that other lifestyle factors, such as overall diet,
  obesity and sedentary behavior, may have an equal of higher effect on NAFLD
  classification. Given the design of this study, it is not possible to isolate
  the effect of a single factor. Further, no conclusions about cause and effect
  can be drawn.

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